An Overview of Injection Site Reactions

Introduction

Injection site reactions are the most common adverse complication of immunization. Pain, itching, swelling, or redness at the injection site are the most common reactions. Most patients experience a mild reaction that can last for one to two days. However, a large reaction extending from joint to joint may develop in a few patients with vaccine administration. The booster dose of diphtheria, tetanus, and pertussis vaccines can lead to severe injection site reactions.

What Are Injection Site Reactions?

Injection site reactions can develop in any site, like the arm, thigh, stomach, or buttocks. Typically injection site reactions are mild, with redness, bleeding, and pain in subcutaneous or intramuscular injections. Mild reactions are easily treated with a cold compress at the injection site, over-the-counter pain medication, or an antihistamine prescription for itching. Some patients may develop a fever following an injection that may require antipyretics.

The inflammatory changes following vaccination appear within a few hours and peak within 24 to 48 hours, and resolve within one week. Reduced range of limb movement is uncommon. Movement of the vaccinated limb will improve lymphatic drainage and prevent stiffness.

What Are the Causes of Injection Site Reactions?

Injection site reaction can develop when injection causes irritation to the skin or tissues, medicine, or the immune system is stimulated to react. Subcutaneous injection induces injection site reaction frequently. Irritant reactions can develop within a couple of hours, whereas immune-mediated reactions take a few hours to develop. Medications like Stelatra are frequently responsible for injection site reactions.

What Is the Symptom of Injection Site Reactions?

The most common skin changes are:

• Redness.

• Warmth.

• Swelling.

• Itching.

• Lump under skin.

• Mild pain or discomfort at the injection site.

What Are the Most Common Injection Site Reactions?

• COVID-19 (Coronavirus) Vaccine: If there is an injection site reaction occurring with the first dose, then the reaction may be reported with subsequent follow-up doses. In a few patients, delayed reactions to COVID-19 vaccinations were noted. The symptoms developed four to 11 days following vaccination.

• Flu Shot: Injection site reactions are reported with yearly flu vaccines.

• Tetanus Shot: Injection site reactions are reported with booster shots for tetanus.

• Chemotherapy Injections: In cancer patients, injection site reaction can be of two types: flare and extravasation. Flare is a localized reaction caused by irritant drugs. The symptoms of flare reaction are similar to mild injection site reaction. Extravasation is a more severe type caused by leakage of chemotherapeutic agents like vesicants at the site of injection. The extravagant type of reaction includes pain, blistering, and severe skin damage at the site of injection. Leakage of highly toxic and corrosive chemotherapeutic agents like vesicants may induce damage to adjacent tissues.

• Pneumococcal Vaccines: The vaccines are administered to children and adults to prevent pneumococcal infections. Children develop reactions within 24 to 48 hours of vaccine administration, while for adults over 70 years, the reaction appears after three days of vaccination.

• Mounjaro Injection Site Reaction: It is an injectable prescription medicine for treating diabetes. Injection site reactions are mostly mild and resolve on their own. Applying an ice pack following injection or changing the location for each injection can limit injection site reaction.

What Are the Adverse Effects Occurring Due to Improper Injection Technique?

Shoulder injury due to vaccine administration can develop due to improper injection technique. It is a serious complication that develops from directly injecting the vaccine into the shoulder capsule instead of the deltoid muscle. The diagnosis of the condition is difficult, and it requires immediate medical intervention.

To prevent shoulder complications, proper injection techniques must be followed. While administering intramuscular injections, the deltoid muscle location must be confirmed, and the vaccine must be administered deep into the middle at a 90-degree angle.

What Is the Treatment for Injection Site Reaction?

Most of the injection site reactions resolve without a need for treatment.

• Over-The-Counter (OTC) Medicines: Relief from pain can be obtained from painkillers like Advil or Tylenol.

• Medication for Itching: OTC antihistamine and Diphenhydramine may provide relief from itching at the injection site.

• Hot Compress: In reactions caused by chemotherapeutic agents like vinca alkaloids drugs, hot compress is used for treatment. The hot compress is applied for 10 to 20 minutes to soothe the irritated muscles at the injection site.

• Cold Compress: In cancer patients, if the reactions are not induced by vinca alkaloids, a cold or ice compress is used for mild reactions. A cold compress can soothe redness, swelling, warmth, and itching. An ice pack is placed on the irritated area for 10 to 20 minutes to obtain relief. The ice packs must be wrapped with towels before application.

• Antidote: Cancer patients with extravasation reactions have antidotes that depend on the types of drug-inducing reactions.

• Plastic Surgery: Extensive damage to the injection site may require plastic surgery.

How to Prevent Injection Site Reactions?

• Immediately after injection, applying a cold compress for 5 to 10 minutes can limit injection site reaction.

• Irritant injections can be taken at a lower dose to avoid injection site reactions.

• Most skin reactions develop due to carriers or preservatives present in injections. Therefore, changing the injection brand may reduce injection site reactions.

• In individuals, self-administering injections, changing the injection site may reduce the risk of injection site reactions.

• Following proper injection administration techniques can limit reactions.

• Injections stored at a cool temperature must be brought to room temperature to reduce pain and injection site reactions.

• Irritated skin with rash, cut, or eczema (skin inflammation) must be avoided since they are most likely to produce reactions.

• A thinner needle of 25 gauge may be used to reduce injection site reactions.

• Avoid smoking as smoking increases the risk of developing injection site reactions.

When Is the Injection Site Reaction of Concern?

Symptoms of a severe allergic reaction include fever, trouble breathing, hives, swelling of the face, lips, or tongue, nausea or vomiting, extreme fatigue, blisters at the injection site, severe pain at the injection site, and trouble in movement.

Conclusion

Injection site reactions are commonly seen after the administration of immunization injections, cancer drugs, or medicines. The symptoms may be mild, severe, localized, or extensive in nature. The symptoms appear within a few minutes, hours to days after injection administration. Most of the symptoms resolve without treatment, whereas severe reactions require medical attention. The injection site reaction is of concern when the anaphylaxis reaction develops. Carefully following injection protocols and post-injection care can minimize injection site reactions.